Out of interest, who are "these guys" you are referring too?
If they are failing the upgrade in statistically significant numbers, it begs the question who or whom deemed that these individuals are suitable and capable of passing the upgrade.
It's also worth understanding if there is a specific sylabus in place, and are these individuals devoting their time into understanding the areas that the training department, company, and GCAA deem necessary to become a competent commander?